A cellular network provides wireless access for user equipment (UE) (e.g., mobile phones, computers, transceivers, etc.) for purposes of communication. The network includes multiple cells, each supported by a base station that is used for transmitting and receiving communication signals. Collectively, the cells provide wireless, radio coverage over a large geographic area. In this manner, UEs are able to communicate with each other throughout the cellular network. Additionally, the cellular network is able to connect with other networks (public switched telephone network, other cellular networks, internet based networks, etc.) to facilitate communication between devices connecting to any of the available networks.
In order to transmit information (e.g., voice, data, etc.) over the cellular network, a UE must first perform a network connection or initial entry setup with a serving cell in order to identify and validate itself to the network. This occurs under various scenarios while the UE is within the geographic boundaries supported by the cellular network. To name a few instances, the UE performs an initial entry setup with a supporting cell of the cellular network when the UE powers on, transitions from an idle to active state, makes a bandwidth request for uplink data transmission, transmits location information, or performs UE re-synchronization when the uplink is out of synchronization or when a failure occurs on the uplink.
Current UE network access schemes are associated with a cell and its cell identifier. This cell-based scheme allows for a UE to communicate through the cellular network by obtaining an access signature sequence for use with the serving cell. That is, once the UE has been identified and validated during the initial entry setup, the UE will be assigned a signature sequence by the serving cell for UE cell-based access activities with the cellular network.
However, there are a limited number of access sequences per cell. For instance, there may be only 64 access sequences that can be used throughout a single cell, as in a fourth generation long term evolution (4G LTE) cellular network. Because of this limited number, UEs release their access sequences when not in use to make them available to other UEs actively requiring service from the cell. For instance, after a period of communication inactivity (e.g., as established through expiration of a timer) a UE releases its access sequence and goes into an idle mode in terms of communication with the cellular network. Transitioning back to an active mode from the idle mode may require performing an additional initial entry setup process. Reperforming the initial entry setup makes the connection setup very long and inefficient.
Also, because the network access scheme is based on a servicing cell, when a UE moves from one cell to another, the UE has to get a new access signature that is assigned by the new cell through the current serving cell. This handover process should be completed when the UE can switch to the new cell. When successful, the handover process avoids performing an initial entry setup process. Unfortunately, because the handover process occurs on one or more cell boundaries, the signal strength of the airlink is limited which possibly results in a poor link between the UE and the serving cell. As such, whenever the link is lost, the UE must again perform the costly initial entry process with the new cell in order to connect back to the network. The inefficiency is further exposed when the UE ping-pongs or moves back and forth between the two cells, requiring increased signaling overhead for the same UE accessing the cellular network.
Moreover, future networks may exhibit increased transmit node densification in order to increase radio access capacity. For instance, transmit point virtualization is a way to handle inter-transmit point interference. With transmit point virtualization, the traditional fixed one-to-one mapping between a UE and a cell no longer exists. Instead, a network can dynamically select the best transmit/receive points to serve a particular UE, wherein the transmit point selection is transparent to the UE. As a result, the current UE/cell based network access scheme may not be compatible with transmit point virtualization.
The current UE/cell association access scheme is inefficient as it a UE may have to perform multiple, costly initial entry setup processes within a cell boundary or when performing a handover process. In addition, the current access scheme may be unsuitable for high density UE terminals and devices (e.g., smart meters, etc.). Furthermore, the current access scheme may not be applicable to future wireless networks, in which two or more transmit/receive points may serve one UE to enhance communication link quality, or where the number of transmit/receive points serving one (e.g., mobile) UE can vary with these network configurations being transparent to the UE.